Air quality has improved since 2000 and holds up well in comparison to other European countries. Most limit values are complied with, but ozone, particulate matter and nitrogen compounds continue to harm health and ecosystems. Further action is needed in agriculture, in transport, in industry and in heating. Progress is possible through the systematic use of the best available technology.
1. Mobility, energy use, industrial and agricultural production (drivers)
Transport performance in Switzerland has been continually rising since the mid-1990s. Some three quarters of passenger transport performance (land transport only) is accounted for by motorised road transport. The measures introduced to combat the COVID-19 pandemic, such as the working from home mandate, led to a decline in transport performance in Switzerland in 2020 for the first time since the mid-1990s.
The demand for mobility and for goods transport will continue to increase according to the Transport Prospects 2050, and traffic will continue to grow in the future. However, it will grow more slowly than the population due to social and economic trends such as the increase in working from home, continuing urbanisation and population ageing.
Petrol and diesel cars will increasingly be replaced by electric vehicles, while walking and cycling will become more popular, particularly in urban areas. These trends will help reduce air pollution. In addition to traffic, the quality of the air is also influenced by energy consumption and consumer behaviour, the operation of industrial and commercial installations, and agriculture.
Natural processes, such those of microbial and chemical processes in the soil and water bodies, the secretions of plants and animals, erosion, forest fires, and lightning also have an effect, but their impact on overall air quality in Switzerland is typically relatively modest.
2. Pollutant emissions (pressures)
The main causes of current air pollution are the following:
- motorised transport (nitrogen oxides (NOX), particulate matter, volatile organic compounds (VOC) and soot),
- households, including wood combustion (particulate matter, VOC and soot),
- agriculture (ammonia, VOC and particulate matter)
- industry (VOC, NOX and particulate matter)
The pollutants are carried by air currents and can change chemically and physically during transport. Ozone (summer smog) is produced from the precursor pollutants nitrogen oxides (NOX) and volatile organic compounds (VOC). 'Secondary' particulate matter can be formed from ammonia, VOC, NOX and sulphur dioxide.
Emissions of most pollutants have fallen further since 2000. However, the reduction targets specified in the Federal Council’s Air Pollution Control Strategy 2009 have not been achieved to date, except for sulphur dioxide and NMVOCs.
- The source of the particulate matter emissions (PM10, PM2.5) is divided in almost equal parts between industry and transport and, to a lesser extent, agriculture and households. PM10 emissions decreased by 26% between 2005 and 2020. The target of PM10 is a reduction of 45% compared to 2005. However, PM2.5 emissions decreased by 45% since 2005.
- Over half of the nitrogen oxide emissions are caused by transport. Total emissions decreased by 44% between 2005 and 2020. The target is a 50% reduction.
- Concerning volatile organic compounds (VOC), 45% are produced by industry and 28% by agriculture (as at 2020). The target is a reduction of around 30% compared to 2005. With a reduction of 41% to date, this has been achieved.
- Ammonia (NH3) originates almost exclusively from agriculture, where it escapes into the air from stables and liquid manure storage and application sites. Total ammonia emissions, which are responsible for around two-thirds of the nitrogen deposition, have only decreased by about 11% since 2005. The target is a reduction of 40%.
3. Ambient concentrations of pollutants (state)
Air quality in Switzerland has continued to improve since 2000 and holds up well in international comparison with similarly densely populated regions. For most air pollutants for which the Ordinance on Air Pollution Control specifies ambient limit values, the levels throughout Switzerland are now below these limits.
In contrast, the measured concentrations of ozone (O3) exceed the ambient limit values over a large area, of particulate matter PM10 and PM2.5 at several locations and of nitrogen dioxide (NO2) at individual locations near traffic.
Excessive nitrogen inputs, two-thirds of which come from ammonia (NH3) emissions and one-third from NOX emissions, impact the environment to an extent that significantly exceeds the critical loads. Suffering from nitrogen pollution above the critical level are:
- almost all raised bogs
- almost 90% of forests
- three quarters of fens
- one third of dry meadows.
4. Consequences for people and the environment (impact)
Excessive levels of particulate matter, ozone and nitrogen dioxide pose the greatest threat to health as they cause and exacerbate respiratory and cardiovascular diseases. According to a report on external costs and benefits of transport in Switzerland, the current state of the air led to around 2,300 premature deaths in 2018, including around 200 from lung cancer. Year on year, elevated air pollutant concentrations in Switzerland are responsible for over 1,800 hospital admissions due to cardio-vascular diseases and respiratory disorders and a total of 14,000 hospital days.
High levels of nitrogen in the air cause widespread over-fertilisation of ecosystems. This causes a loss of biodiversity and contributes to the acidification of forest soil and is especially harmful for forests, species-rich meadows and grasslands, alpine pastures, and raised mires and fens. Numerous species that have adapted to low-nutrient habitats are, therefore, endangered as a result of over-fertilisation. In the soil, nitrogen can be transformed into climate-active nitrous oxide.
In agriculture, air pollution (i.e. by ozone) can result in harvest losses of up to 15%.
Air pollutants accelerate corrosion of materials and therefore cause damage to buildings and cultural monuments.
Air pollution costs billions every year in Switzerland. These external costs, which cannot be passed on to the polluters, relate to healthcare, harvest losses, and damage to buildings and materials. The Federal Office for Spatial Development ARE has calculated the total annual health costs to be over CHF 6 billion.
Soot particles, methane, nitrous oxide and ground-level ozone are air pollutants that also influence the climate.
5. Legislative provisions on emissions (responses)
Even if there is no immediate risk to the environment (precautionary principle), in order to protect human beings, animals, plants and their habitats against the harmful effects of air pollution, the relevant legislation must ensure that pollutant emissions are kept at the lowest possible level that is economically viable and technically feasible. More stringent restrictions are imposed, if it is assumed that harmful effects will arise.
Federal regulations exist for pollutant emissions from heating systems, industrial installations, motor vehicles, machinery and equipment, ships and rolling stock as well as for the quality of combustibles and heating fuels.
Moreover, state-of-the-art technology should be used in motor vehicles, industrial and agricultural machinery, and heat generation systems. The Euro-6/VI standards for motor vehicles, which have been in force since 2014 and are gradually being tightened, have introduced – albeit with some delay – further improvements in relation to particulate matter and nitrogen oxide emissions. Moreover, measures are being developed to reduce abrasion of fine particles in brakes and tyres.
Other measures that have been implemented include the heavy vehicle charge and the incentive tax on volatile organic compounds (VOCs).
To reduce the ammonia emissions generated by livestock farming, slurry storage facilities in agriculture must be firmly covered by 2030 so that less ammonia escapes. Additionally, manure must be applied using low-emission systems (e.g. drag hoses) from 2024. In addition, low-emission barn construction is promoted with financial contributions.
The cantons have developed action plans to protect the air by reducing pollution at the local level, for example by promoting the use of public transport or imposing temporary bans on wood-fired systems.
Synergies with other policy areas occur particularly in the area of energy and climate policy. Measures to increase efficiency and replace fossil energies with renewable ones are usually consistent with air pollution control policy.
In addition, long-term measures are needed to reduce large-scale air pollution in other European countries. This means that further action is required at international level within the context of the Convention on Long-Range Transboundary Air Pollution.
Last modification 20.12.2022